I recently ran into this issue on a lilac site. Plants that I called dark pink were called purple. Lavender was called blue.

This makes it tough to help a customer who wants a purple lilac.

There are several places where this process can go astray:

1. What is the lighting. Sure, you took the picture outside, but a cloudy day has bluer light than a clear day. Northern shade lighting is MUCH bluer than sunlight. If there is smoke from forest fire, or it's close to the day's end, the light is tinged with yellow or red.

The human eye adapts. You often won't notice a color shift out there, but once you are in a more colour neutral environment the pictures you just took look wrong.

2. What does your camera do to the image? Most modern digital cameras have 'auto white balance' that is supposed to compensate for these colour shifts, and most of the time they work well. But they assume that the world averages out to grey. If 3/4 of the view is a vivid red rose, then your camera may think that you are shooting near sunset, and blue it up for you. You may need to play with settings to neutralize this.

3. Is your idea of "purple" the same as mine? Shade names on this part of the color wheel are notoriously sloppy.

4. Is your screen the same as mine. Not only screen, but surrounding light. People who edit photos for a living create a room with neutral colours

What are we to do?

Here's an easy solution: Go to your local building store and collect paint samplers. (As a challenge: Try to pick a set that is a close match to the flowers you normally may shoot. Anyway get 12 to 20 colours, split across the spectrum. Split them between fairly saturated colours, and pastels.

Now go take pictures, but in each picture include 4 paint samples. NOW you have a picture that you can compare next winter when you are writing your garden catalog.

You can take a photo of all the samples together, and label them "Pink, Purple, Red,..." AND give them the color sample name. They can go to their own Home Depot and pick up the same color sample.

Another trick that helps: Have a piece of pure white paper somewhere in the photo. Put it where you can crop it out later.

In your photo editing software, you probably have a 'white point' setting tool. You know the paper is white. Click on it, and tell your program, "this is white" Note that to do this, you may need to underexpose slightly.

Photo stores sell "grey cards" This is a piece of cardboard that has reflects 18% of the light that hits it. Doesn't matter what colour the light is, 18% is reflected. Putting this in the picture somewhere may help you get better pics.

Turn off the auto white balance when shooting. Set it manually to whatever condition is closest. This way, you will have the same error on each picture. This can make it easier at your desk. Fix one, and apply that change to all. You don't have to have the grey card in every picture that way. (Include it in enough pix however to catch changes in the lighting as you move around, as the clouds come in, as the sun sets.